Optical disc apparatus and method thereof

ABSTRACT

An optical disc apparatus and method for recording and reproducing information to/from an optical disc, including discrimination of the optical disc, reading control information in an un-recordable area formed in an inner periphery of the optical disc, conducting focus control based on a focus error signal in a recordable area formed outside of the un-recordable area, and determining an optimum offset value of the focus error signal in the recordable area. Further, adjustment in amplitude of a reproduced signal from an inner periphery of the recordable area is conducted, test-writing in the inner periphery of the recordable area is conducted, test-writing in an outer periphery of the recordable area is conducted, and adjustment in amplitude of a reproduced signal from the outer periphery of the recordable area is conducted. The respective operations are conducted sequentially so as to make the optical disc in a reproducible and recordable condition.

CROSS REFERENCE TO RELATED APPLICATION

This is a continuation of U.S. application Ser. No. 09/968,968, filedOct. 3, 2001, now U.S. Pat. No. 6,438,078, which is a continuation ofU.S. application Ser. No. 09/291,216, filed Apr. 14, 1999, now U.S. Pat.No. 6,301,210 the subject matter of which is incorporated by referenceherein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a reproducing apparatus and a method ofan optical information recording medium for reproducing recordedinformation from the optical information recording medium in which theinformation is recorded on a disc-like medium with pits or the like, ora recording/reproducing apparatus being further possible to recordinformation (hereinafter, it is called only by a recording/reproducingapparatus of an optical information medium), and in particular to anoptical disc apparatus for performing the recording/reproducing ofinformation on a medium of so-called a land-groove method.

2. Description of Related Art

Conventionally, various kinds or types of recording/reproducingapparatuses for optical information recording medium are already knownand are in practical use, which read out the recorded informationoptically for reproduction thereof, from an optical informationrecording medium on which the information is recorded by forming pitswith use of so-called a phase-change or the like on a disc-like opticalrecording medium. In particular, recent years, an optical recordingmedium, being able to record a large amount of information with highdensity in the recorded information, was proposed and attractingattentions, for example that called by a VD (digital video disc), andalso a reproducing apparatus for reading out the information thereof, apart thereof, is already available on a market.

However, with such the high density recording medium including such asthe DVD, etc., for the purpose of increasing the density in informationrecorded on the disc-like medium, a laser beam is applied to, beingshorter in the wavelength than that used in previous, and further forthe purpose of increasing the density in track pitch, a concave portionand a convex portion, being called groove area and land arearespectively, are formed on the recording surface of the medium, so asto record the information in those areas. More, the land area or thegroove area appears alternatively for each round, following a tackingoperation by an optical pickup as an optically reproducing means. Also,as such the high density recording mediums, there are proposed variouskinds of recording mediums, such as a recording medium which enablesonly reproduction of the information recorded, a recording medium whichenables recording of only one-time, and further a recording medium whichenables a plurality of times of recordings, etc. However, among thosekinds of the recording mediums, characteristics or properties aredifferent to one another, in particular in reflectivity or reflectionfactor thereof.

On a while, in a recording/reproducing apparatus of optical recordingmedium for reproducing the recorded information from such the highdensity recording medium, in which such the concave and the convexportions called as the land area and the groove area are formed,conventionally, a control is applied for controlling a focus position ofthe optical reproducing means thereof, in which the focus position forthe land area and the focus position for the groove area are exchangedalternatively, for each round, in synchronism with an address signalrecorded in an area defined between the land area and the groove area,namely called by a pit address, in advance.

Also, from conventionally, a high reliability of the information isachieved by conducting a so-called verify control, i.e., it is confirmedwhether the recorded data can be reproduced correctly or not whenrecording information onto the optical recording medium.

However, with such the high density recording medium, for correctlyreproducing the information recorded with high density or for recordingit, there are necessitated initialization of various devicesconstructing the optical disc apparatus and control of operations forperforming the recording/reproducing smoothly. In particular, with suchthe apparatus necessitating such the accurate control, manyconfirmations must be performed from a turning ON of a power supply upto a ready condition, i.e., the information can be read out from theoptical disc correctly.

For example, in the optical disc apparatus, it must be decided whetherthe optical disc is inserted or not, first, under the condition wherethe power supply is turned ON, and further, whether the optical disc isa CD-ROM, a DVD-ROM or a DVD-RAM. Setting condition varies for thosedifferent optical discs, therefore it is very important.

Also for the high density recording medium mentioned above, for thepurpose of reproducing the information recorded with high density, it isnecessary to control an optical pickup as the optical reproducing means,in particular the focus position of the focus lens, with higheraccuracy. Ordinarily, with the recording/reproducing apparatus foroptical information medium, the focus position is adjusted so as to becontrolled at an appropriate position obtained in advance when beingshipped, however, it is important to control the focus position at anappropriate position in conformity with, for example, the kind and/orcondition of the recording medium, and further an environment of use ofthe apparatus, including the temperature and so on. For that purpose,modifying the focus position to an ideal position is conducted on abasis of the recorded data which is reproduced actually with theapparatus by applying a control, such as a learning control, etc.

Further than the above, the confirmation must be made on manyoperations, including such as presence of a cassette, selection of theoptical pickup, adjustment of tracking, adjustment of writing in, etc.

SUMMARY OF THE INVENTION

An object, according to the present invention, for dissolving suchproblems as mentioned, is to provide an optical disc apparatus beingable to be in a condition where the reading and writing can beperformed, with smoothly confirming the operations in a short timeperiod.

According to the present invention, for accomplishing the objectmentioned above, there is provided an optical disc apparatus forrecording and reproducing information of an optical disc, comprising:

-   -   means for discriminating the optical disc;    -   means for reading control information in an un-recordable area        which is formed in an inner periphery of said optical disc;    -   means for conducting focus control in a recordable area which is        formed outside of said un-recordable area;    -   means for conducting adjustment in amplitude of a reproduced        signal from an inner periphery of said recordable area;    -   means for conducting test-writing in the inner periphery of said        recordable area;    -   means for conducting test-writing in an outer periphery of said        recordable area; and    -   means for conducting adjustment in amplitude of a reproduced        signal from the outer periphery of said recordable area, wherein        said means conducts the respective operations sequentially, so        as to make said optical disc in reproducible and recordable        condition. And, more preferably, according to the present        invention, there is provided the optical disc apparatus as        mentioned above, further comprising means for conducting a        pre-writing (a sample-writing), wherein said means conducts the        pre-writing between the operation of discriminating of said        optical disc and the operation of test-writing in the outer        periphery of said recordable area.

According to the present invention, for accomplishing the objectmentioned above, there is also provided a method for making an opticaldisc in reproducible and recordable condition with use of an opticaldisc apparatus for recording and reproducing information of the opticaldisc, comprising following steps:

-   -   discriminating the optical disc;    -   reading control information in an un-recordable area which is        formed in an inner periphery of said optical disc;    -   conducting focus control in a recordable area which is formed        outside of said un-recordable area;    -   conducting adjustment in amplitude of a reproduced signal from        an inner periphery of said recordable area;    -   conducting test-writing in the inner periphery of said        recordable area;    -   conducting test-writing in an outer periphery of said recordable        area; and    -   conducting adjustment in amplitude of a reproduced signal from        the outer periphery of said recordable area, wherein said means        conducts the respective operations sequentially, so as to make        said optical disc in reproducible and recordable condition. And,        more preferably, according to the present invention, there is        provided the method as defined in the above, further comprising        a step for conducting a pre-writing (a sample-writing), wherein        said means conducts the pre-writing between the operation of        discriminating of said optical disc and the operation of        test-writing in the outer periphery of said recordable area.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram of an optical disc apparatus being able toread and write therewith, according to the present invention;

FIG. 2 is an outlook view of the optical disc apparatus according to thepresent invention;

FIG. 3 is an outlook view of an optical disc, such as DVD, which can bereproduced or recorded by the optical disc apparatus according to thepresent invention;

FIG. 4 is a cross-section view of the DVD shown in FIG. 3, in particularin a land area and a groove area of an information recording portionthereof;

FIG. 5 is an explanatory view of explaining a forming format of the landarea and the groove area in the DVD shown in FIG. 3;

FIG. 6 is an enlarged perspective view of a pit address area definedbetween the land area and the groove area in the DVD shown in FIG. 3;

FIG. 7 is a circuit diagram of showing the circuit construction of theoptical disc apparatus according to the present invention;

FIG. 8 shows wave-forms at various portions in the optical discapparatus according to the present invention;

FIG. 9 is a flow chart of showing steps of the optical disc apparatusaccording to the present invention, until a ready condition thereof;

FIG. 10 shows a graph in which the horizontal axis indicates acircumference temperature and the vertical axis a signal amplitude (DACvalue);

FIG. 11 is a flow chart of pre-writing of the optical disc apparatusaccording to the present invention;

FIG. 12 is a flow chart of showing a focus control method;

FIG. 13 is an explanatory view for explaining on a pit addressacknowledgeable area in concrete, which is set by the focus controlmethod shown in FIG. 12;

FIG. 14 is a flow chart for explaining a learning control for a focuscontrol;

FIG. 15 is an explanatory view for explaining about an optimal FEoff-set value for each sector, which is set with the learning controlshown in FIG. 14;

FIG. 16 is an explanatory view for explaining about an optimal FEoff-set value for each sector, which is set by averaging in the learningcontrol shown in FIG. 14;

FIG. 17 is a flow chart for explaining the learning control for a focuscontrol but according to an another embodiment; and

FIG. 18 is an explanatory view for explaining about the optimal FEoff-set value, which is set with a maximum amplitude and a decreasingrate in the learning control shown in FIG. 14, with simplificationthereof.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, detailed explanation of the embodiments according to thepresent invention will be given by referring to attached drawings.

First, the construction of an outline of an optical disc apparatusaccording to the present invention will be explained by referring toFIG. 1. This FIG. 1 shows a block diagram of the optical disc apparatusbeing able to read and write an optical information recording medium ofan embodiment.

First, in FIG. 1, a reference numeral 100 indicates an optical disc ofthe high density recording medium, a reference numeral 2 indicates anoptical pickup, inside which are provided a semiconductor laser 210 as alight emitting element for emitting a laser light beam of a desiredwave-length, a condenser optical lens 220 for turning the laser lightemitted into a parallel light, a half-mirror 230 for penetrating aportion of an incident light as well as for reflection the otherportion, a mirror 240 for changing a direction of the light, a focuslens 250 for irradiating the laser beam focused to a predetermined beamdiameter onto a recording surface of the above optical disc 100, and anlight receiving element 260 for receiving and detecting a refectionlight from the above half mirror 230, etc. Here, a reference numeral 261indicates an another front light receiving element for receiving anddetecting the reflection light from the above half mirror 230, whereinthe signal obtained through the said front light receiving element 261is compared with a target voltage for reproduction by means of acomparator not shown in the figure but provided in a signal processingportion 300, and a predetermined signal is feedback to a laser drivercircuit 500 so as to make them equal. By means of this feedback loop,the intensity or strength in emitting light of the laser is controlledwhen reproducing the information.

Here, in this embodiment, in order to change the focus distance of thecondenser lens 220 in conformity with the thickness of the optical lens100, it is constructed with two objective lens for use in the DVD andthe CD. This pair of the two condenser lenses 220 can be exchanged by amechanism of moving quickly in horizontal direction. Ordinarily, in acase where a tracking servo is in operation, since a stabilizing pointlies in or at an optimal position, it is possible to move the lensmomentarily in horizontal by giving a kick-pass signal to a trackingcontrol system when shifting the lens, so as to fall in the stabilizingpoint of tracking of the other lens.

Further, in FIG. 1, a reference numeral 300 indicates the signalprocessing portion for conducting a predetermined process by convertingthe reflection light into electrical signal, being detected with thelight receiving element 260 of the optical reproducing means mentionedabove. This signal processing portion 300 is connected to amicro-computer 400 provided for controlling the optical disc apparatus,the reproducing apparatus of optical information recording medium,totally, thereby performing various controls including a focus controlwhich will be mentioned in details below. Namely, this micro-computer400 is connected further to a laser driver circuit 500, a shiftcontroller circuit 600, a spindle controller circuit 700, and atwo-dimension actuator control circuit 800.

Namely, with such the construction mentioned above, the micro-computer400 control the intensity of the emission light by controlling currentsupplied to the semiconductor laser 210, i.e., the light emittingelement of the optical pickup of the optical reproducing means mentionedabove, and also control the position of the above optical pickup 200 inthe radial direction of the optical disc 100 by controlling the rotationof a motor 650 for shift control. In this embodiment, as a mechanismshifting in the radial direction of the optical disc 100, there isindicated a gear 660 for moving the optical pickup 200 into the radialdirection by rotation of the above motor 650 for shift control. However,this should not be restricted to it.

Also, the micro-computer 400 realizes a control of a linear velocityconstant which is widely adopted in such the high density informationrecording medium, such as a LVC (constant linear velocity) or a ZCLVC(zoned constant linear velocity), etc., by controlling the rotation of amotor 750 which rotationally drives the spindle. In particular, in theZCLVC of the latter, a revolution number (or angular velocity) iscontrolled to be constant in each zone, and the revolution number ischanged for every zone. Further, this micro-computer 400 realizes thefocus position control of the focus lens 250 in the above optical pickup200, with electromagnetic function by use of an electromagnetic coil 850or the like, as an actuating means for example, through thetwo-dimension actuator control circuit 800. However, the two-dimensionposition control of the focus realized with this two-dimension actuatorcontrol circuit 800 includes, in addition to the position control of thefocus lens 250 in a direction perpendicular to the recording surface ofthe above optical disc 100, further the tracking position control fortracing the track with minute position adjustment in the radialdirection perpendicular thereto, and the exchange between theabove-mentioned two optical lenses for condensing light.

The block of the apparatus shown in FIG. 1 is, ordinarily, received in ahousing or case shown in FIG. 2 for example, so as to constitutes aoptical disc apparatus. In this optical disc apparatus is provided atray being provided with an insertion mechanism, not shown in thefigure, but being attached within the housing in able to project andsetting the optical disc onto the above motor 750 to be ratable thereon.The CD or the DVD-RAM, etc., ordinarily, only the disc itself is mountedon the tray TR to be inserted into the apparatus, however, in particularfor the DVD-RAM, as shown in FIG. 2 for example, sometimes it isreceived within a case called as a cartridge C to be used, therefore thetray TR is so constructed that also the cartridge C can be mountedthereon. For coping with both modes in use of the disc (i.e., the discis used as itself, or is used being received within the cartridge), thetray TR are provided with guiding groove G1 and G2 in use for a discitself, being coincide with disc diameters 8 cm and 12 cm respectively,and is provided with claws or nails for fixing the cartridge thereon.Further, in this embodiment, a detection means (a switch or a sensor) isprovided for detecting the presence of the above cartridge C. This isbecause, the optical disc using the cartridge C is the DVD-RAM only atthe present time, therefore the optical disc can be easily identified tobe the DVD-RAM by confirming the presence of the cartridge C.

Then, according to this embodiment, an command or an information datafrom a host, of such as a personal computer, not shown in the figure, isinterpreted with an interface controller circuit, while therecording/reproducing and seek operations of the information beingexecuted through a microcomputer 400, and it is recorded on the opticaldisc 100 through the optical head after being converted by a signalmodulator processing portion 300. Also, various kinds of signals beingread through the light receiving element 260 are de-modulated back tooriginal date through the signal processing portion 300, and thede-modulated data can be transferred from the interface controllercircuit to the host responding to a reproduction command.

Also, during the recording/reproducing, the various kinds of controlinformation being recorded in the optical disc 100 are reproduced by thesignal processing portion 300, so as to be used for controls of thevarious kinds of devices and/or apparatuses mentioned above.

Next, by referring to FIGS. 3 through 5, the optical disc 100 as thehigh density recording medium being called VD-RAM will be explained indetails. FIG. 3 shows an outlook of the DVD as the high densityrecording medium, from and into which information will be reproduced andrecorded by means of the recording/reproducing apparatus for opticalinformation recording media, and in particular, FIG. 3(a) shows aperspective view, and Fig. (b) a plane view thereof. FIG. 4 shows across-section view of the land area and the groove area of theinformation recording portion in the DVD shown in FIG. 3. FIG. 5 is forexplanation view of a forming format of the land area and the groovearea in the DVD as one of the high density information recording media,in particular, FIG. 5(a) shows the construction of the land area and thegroove area, and FIG. 5(b) explains the format of each area of them.FIG. 6 is an enlarged view of a portion for showing a pit address areadefined between the land area and the groove area in the DVD.

First, an explanation will be given on the optical disc 100, i.e., theDVD-RAM shown in FIG. 3. Among such the optical discs, in particular,with the recordable medium being called by VD-RAM it is possible towrite information by forming pits in the recording layer within thesubstrate, with use of phase change due to irradiation of such as thelaser light. And, thereafter, the information is reproduced with thepits which are written in it. Or, with the read-only medium being calledby VD-ROM the laser light is irradiated upon the recording surface onwhich information is written previously, and the recorded information isreproduced by the reflection light thereof.

However, the optical disc 100 shown in FIG. 3 is only one example of theoptical information recording media, such as the recordable mediumcalled by VD-RAM and can be divided into a ROM portion at a centerthereof, into which predetermined control information is recorded, and aRAM portion 120 facing around thereof. With such the high densityreceding medium as mentioned in the above, on the RAM portion 120 as theinformation recording area is formed a spiral track T thereof for thepurpose of recording the information on the disc continuously, and atthe same time, for the purpose of increasing the recording densitythereof, it is formed divided into concave and convex area, which arecalled as the land area and the groove area, respectively, so as toenable the recording/reproducing of the information.

Further, the RAM portion 120 mentioned above is divided into severalareas. Namely, at an inner side and an outer side of the RAM portion areprovide areas 121 and 122, into which the information relating to thecontrol of the apparatus is recorded, and further between them isprovided a user area 123 into which the information of the user can bewritten.

Moreover, the above-mentioned writing area 121 is divided into an area121 a for the disc information and an area 121 b for the apparatusinformation. The area 121 b for the apparatus information is used uponoperation of test writing which will be explained in details later.Also, the user are 123 is constructed with a plurality of areas 123 awhich are further divided in plurality in the radial direction thereof.Further, at the each most-outer periphery of the above areas 123 a areprepared is prepared an alternative block, which can be the recordingarea in place of the area 123 a in inner side thereof when the writingis in failure in it. Each of the alternative blocks will be used,principally, as the alternative block for the corresponding block 123 a,however, it can be used as the alternative block for the other block 123a when it is full. In this instance, the writing is so controlled thatit is conducted into the alternative block being nearest to it.

Next, FIG. 4 shows the cross-section of the land area and the groovearea of such the information recording area. In this figure, the landare is indicated with a mark while the groove area with wherein thoseland area L and groove area G are formed one by one in the radialdirection of the disc-like recording medium 100 and in those land area Land groove area G are formed the so-called pits, as indicated withbroken lines in the figure, so as to record the information therewith.

Further, in FIG. 5 are indicated the forming format of theabove-mentioned land L and groove area G in such the high densityrecording medium, wherein the land area L is indicated by a hatchedarea, while the groove area G is defined therebetween. Those land L andgroove G areas are formed with exchanging between the land area L andthe groove area G alternatively by an unit of one round of the disc-likeoptical disc 100. In this figure, the land area L and the groove area Gare exchanged on the boarder of the portion indicated by a one-dottedchain line. Further, those land L and groove G areas are formed withunits being called as sectors of from 17 to 34 in the number thereof,per a unit of one round of the track on the disc, respectively, andthose sectors are divided by the area which is called as the pit addressarea PA therebetween. Furthermore, the RAM area 120 in the disc isdivided into the areas 123 a in the direction from inner periphery toouter one. Each of the above areas 123 a is constructed with the samenumber of sectors therein.

In FIG. 6 is shown the pit address are which is formed between the landarea L and the groove area G. First, in FIG. 6(a) is shown a portionwhere it transit from the land area L to the groove area G (i.e., thepit address area of the portion of the one-dotted chain line in theabove FIG. 5), and then, the laser light for detecting the recordedsignal is shifted from the land area L through this pit address area PAto the groove area G, as is indicated by an arrow of the one dottedchain line in the figure.

On a while, in FIG. 6(b) showing the portion shifting from the land Larea to the land area L, the laser light for detecting the recordedsignal also, as is shown by the one-dotted chain line in the figure, isshifted for example from the land area L through this pit address areaPA to the next land area L. However, when it is shifted from the groovearea G to the next groove area G, it is needless to say but, it alsopasses through the pit address area PA.

In this manner, in the recording medium 100 recording the informationwith high density, the information is recorded in the land area L andthe groove area G alternatively, which are different from each other inthe height thereof, therefore, for reproducing the recorded informationfrom such the recording medium with certainty, it is necessary tocontrol the optical pickup optimally, i.e., the optical reproducingmeans for reproducing the recorded information by use of the reflectionlight of the laser beam, in particular the focus position of the opticallens (i.e., the focus lens) for irradiating the laser beam forreproduction focused on the recording medium surface, with respect tothe respective land area L and groove area G being different in theheight.

Also, at the same time, in the pit address area PA mentioned above, asis apparent from the figure, address numbers on the above recordingmedium 100 are recorded on both sides thereof, by a plurality of pittrain P, P . . . Therefore, for reproducing the information recordedfrom such the recording medium 100, it is necessary to detect thoseplurality of pits, P, P . . . in the pit address area PA, correctly oraccurately.

Then, according to the present invention, in order to control the focusposition of the optical lens in the above optical reproducing meansoptimally, in the reproduction of the recorded information from such thehigh density recording medium 100, there is provided therecording/reproducing apparatus of an optical information recordingmedium, with which the control of the optimal position by applying thelearning control is performed, as well as the pits P, P . . . forrecording the address number in the above pit address area PA can bedetected with certainty.

Though not shown in FIGS. 3 through 6, a wobble groove (wobblingminutely in the radial direction) in radial direction is formed on theborder between the land area L and the groove area G with modulating theaddress information around a predetermined frequency. The number of thewobbling per one round is detected through a wobble detection circuitnot shown in the figure, so as to achieve the rotation control of themotor 750 through the above-mentioned spindle motor 700 with highefficiency and stability.

The pit address area PA mentioned above can be divided into two sectionsin the circumference direction, wherein pits P are formed in each ofthem. And, by comparing ID signals obtained from those two pits P, it ispossible to identify the data in the sectors neighboring to each other.

Next, in the attached FIG. 7, there are shown the detailed constructionof those, including the light receiving element 260, the signalprocessing portion 300 for processing the detected signal as well as theperiphery portions thereof, in particular in the optical pickup 200 asof the optical reproducing means in the optical disc apparatus forrecording/reproducing of the optical information recording medium,according to the one embodiment of the present invention.

As is apparent from the figure, the light receiving element is dividedinto four detector portions A, B, C and D, and the reflection lightincident upon this light receiving element 260 reflected upon therecording surface of the above high density recording medium 100 areconverted into electric signals to be outputted through the detectorportions divided, respectively. Here, the outputs from the respectivedetector portions A, B, C and D divided are inputted into adder circuits301 through 304, thereby being added by (A+C), (B+D), (A+D) and (B+C),respectively. Further, the outputs from the above adder circuits 301 and302 are inputted to an adder circuit 305, thereby being outputted a sumsignal (A+B+C+D) by adding all of the outputs from the above detectorportions A, B, C and D.

Further, at the same time, the outputs from the above adder circuits 301and 302 are inputted into a subtraction circuit 306, thereby beingoutputted a tracking error signal TE at the output thereof, i.e., thesignal for the tracking as is expressed by ((A+C)−(B+D)). From thistracking error signal TE is obtained an ID signal by passing it througha high pass filter (HPF) for high frequency, thereafter. Namely, this IDsignal can be obtained by reading the address number pits P, P . . .shown in the above FIG. 6, as the signal wave-form as shown in FIG.8(A), for example. Further, this ID signal read out is inputted into theabove micro-computer 400, and is acknowledged as the address number foreach of the sectors on the track of the recording surface of the abovehigh density recording medium 100.

On a while, at the same time, after passing through a low pass filter(LPF) 308 for low frequency, this tracking error signal TE is added withan off-set value from a D/A converter 310 by an adder circuit 309. Fortracking control in the groove area, first, the tracking error signal TEis reversed in the polarity thereof through a reverse circuit 312, andfurther is outputted to the above two-dimension actuator control circuit800 through a switch element 315. On the other hand, for the trackingcontrol in the land area, it is outputted to the above two-dimensionactuator control circuit 800 through a switching element 318 thereafter.However, to one of the switching elements, i.e., the switching element318 for passing the tracking control signal for the land (L) area, theabove L/G exchange signal is inputted though a reverse circuit 319.Namely, on the basis of the tracking error signal TE, the trackingcontrol signal for the land (L) area and the tracking control signal forthe groove (G) area are alternatively outputted to the abovetwo-dimension actuator control circuit 800. This output comes to be a TRsignal for controlling the tracking, thereby controlling the position ofthe optical reproducing means 200 in the radial direction through theshift controller circuit 600 in the above FIG. 1. Further, to the D/Aconverter 310 is given the off-set value from the above micro-computerthrough the A/D converter portion thereof. However, an explanation ofthis will be omitted, since it has a little relationship with thepresent invention.

On a while, the signals (A+D) and (B+C) outputted from the above addercircuits 303 and 304 are inputted to the subtraction circuit 311,thereby being obtained the focus error signal FE which can be expressedby ((A+D)−(B+C)). This focus error signal FE is divided into a focuscontrol signal FE for the above land area and a focus control signal FEfor the groove area to be processed, and thereafter controls the focusposition (in a direction perpendicular to the recording surface of thehigh density recording medium 100) of the focus lens 250 of the aboveoptical reproducing means 200 through the two-dimension actuator controlcircuit 800.

Namely, the focus error signal FE, as the output from this subtractioncircuit 311 ((A+D)−(B+C)), is applied with the focus off-set through theadder circuit 314, and is outputted to the two-dimension actuatorcontrol circuit 800. The settings of the off-sets for those groove andland in the D/A 313 and D/A 316 are applied to the adder 314 through ananalogue switch SW 317.

Here, in those D/A converters 313 and 316 are given the off-set valuesfor the focus control in the above groove area G and land area L fromthe micro-computer 400, respectively. Also, into the control input ofthe above switching element 317 is inputted an exchange control signalwhich is also outputted from the micro-computer 400, i.e., the exchangesignal between the land (L) area and the groove (G) area.

Here, in those D/A converters 313 and 316 are given the off-set valuesfor the focus control on the above groove area and land area from themicro-computer 400, respectively. Also, into the control input of theabove switching element 317 is inputted an exchange control signal whichis also outputted from the micro-computer 400, i.e., the exchange signalbetween the land (L) area and the groove (G) area.

Further, the off-set values added to the focus error signal FE throughthe above D/A converters 313 and 316, in the present invention, arevariables which must be learned in the learning control adopted forcontrolling the focus position of the optical lens at the optimalposition. However, when this recording/reproducing apparatus of theoptical information recording medium is shipped out as products, theseare preset at predetermined initial values in advance to be shipped. Thepreset predetermined initial values are memorized in an EPROM as being amemory means of the above micro-computer 400.

Next, the operation flow, starting from turning ON of electric power orinsertion of the optical disc 100 into the tray TR and reaching up tothe condition being able to read/write (i.e., ready condition), in theoptical disc apparatus according to the present invention, will beexplained by referring to FIG. 9.

In FIG. 9, first, when the optical disc 100 is inserted into the tray TRof the optical disc apparatus and the tray TR is also inserted or movedtherein, it is detected, and thereafter a detection is made whetherthere is the cartridge C or not (in step 1001). At the present time,various type of the optical discs 100, such as a CD-ROM, DVD-ROM,DVD-RAM, etc., are already practiced, however only the DVD-RAM isinserted into the cartridge C when it is used. Therefore, it is possibleto identify it to be the DVD-RAM depending on the presence of thecartridge C. On a while, when there is detected no cartridge C, adetection of mis-chucking or wit no disc (in step 1022).

In the step 1022, the optical pickup 200 is shifted into an innercircumference to perform initial settings. In this initial settings,current, voltage, resistance and an addition signal, etc., are set atrespective predetermined values. Thereafter, the focus lens 250 ischanged into that for use of the CD and the semiconductor laser 210 isturned on. Then, a focus sweep is conducted to shift or mover the focuslens 250 up and down directions. A decision is made whether a FOK signalcan be obtained or not in this focus sweep operation or not, anddepending on the result thereof is made the decision on the condition ofmis-chucking or with no disc. Further, the focus lens 250 is changedinto that for use of the DVD and the semiconductor laser 210 is turnedon, thereby performing the same follows to make the decision on thecondition of mis-chucking or with not disc, or of presence of the disc.

Further, in this step 1022, when the optical disc 100 is not fullyinserted into the disc chuck of the apparatus, i.e., the mis-chucking,or when no disc is inserted, i.e., no disc, it is also decided to be inthe condition of mis-chucking disc, and a signal indicating it is sentto a host (i.e., the personal computer, etc.) which is connected to theoptical disc and the step is completed or ended (in step 1023). On thecontrary, when decided to be O in the detection of mis-chucking or nodisc, or the presence of the disc, distinction is made on the disc (instep 1024).

Next, when being decided that the cartridge C is inserted in the step1001, confirmation is made on the condition of the cartridge C (in step1002). In this step 1002, the detection is made on such as thecondition, for example, whether write protection is put on or not, and asignal indicating it is sent if the write protection is put on, in astep 1003. The result of the confirmation on the condition of thecartridge C is normal, then steps for DVD (i.e., steps following thestep 1004).

In a step 1024 for distinction of optical disc, first the disc size isdecided by rotating the motor 750, and then the current, the voltage,the resistance value and the sum signal, etc., are set to the initialvalues thereof, so as to perform the focus sweep operation in the samemanner as in the step 1022. At this time, detection of amplitude of theFE signal is also conducted. The same flows is applied by changing tothe focus lens 250 for the DVD. By comparing those results in decisionswith those which are detected in advance for various kinds of theoptical discs, it is possible to decide or discriminate the kind of thedisc, such as the CD-ROM (1026), etc.

Then, in a case where the disc is decided to be the DVD-RAM and be inthe writable condition, various adjustments are made in the focus andthe tracking, etc., in the steps from the step 1005 to the step 1021,thereby reaching to a ready condition. However, the flows for reachingto the ready condition, such as the steps 1025, 1026 and so on are sameto those for the DVD-RAM, therefore explanation thereon will be omittedhere.

First, the optical disc apparatus conducts reading of management datawhich is recorded in the ROM portion 110 with the flows from a step 1005to a step 1011. In more detail, the optical disc apparatus conducts theadjustment on the S-shaped focus adjustment width and the off-sets ofcircuits (in step 1005), when it decides it to be the DVD-RAM. Next, bychanging over the circuit constants for reading the management data ofthe above RAM portion 110 (in step 1006), the head is shifted to the ROMportion of the most-inner periphery through driving of the focus servo(in step 1007), and then is made a confirmation whether the shifteddestination is the above ROM portion 110 or not (in step 1008). For thisROM portion 110, the tracking error signal TE and the amplitude thereofare adjusted in balance with those in ROM portion 110 (in step 1009).Then, the tracking servo is driven with respect to the ROM portion 110(in step 1010) so as to conduct the reading of the control data (in step1011). The reading of the control data is initiated by positioning thehead at the top of the control signal region, and it is completed bypositioning it at the end thereof. Further, the reason for executing theadjustment starting from the ROM portion is for obtaining a shortenprocessing time. Namely, the optical pickup is located on a stopper atthe internal periphery such as in a servo-off condition where theaddress on the disc is unrecognizable, and this condition, the positionlocates near to the ROM portion rather than to the RAM portion, formoving or accessing to a target position.

Next, the adjustment is conducted in the focus and the tracking for theRAM portion 120 following the flow from the step 1012 to the step 1017.In more detail, first the circuit constants are changed over for readingthe data in the RAM portion 120 (in step 1012), and the optical pickup200 is shifted or moved to the RAM portion 120 so as to make aconfirmation whether the shifted destination is the above RAM portion120 or not (in step 1013). Then, conducting adjustment on the amplitudeof tracking and on balance in the RAM portion 120 (in step 1014),driving the tracking servo to the RAM portion 120 (in step 1015), andalso conducting adjustment on the focus gain and the tracking gain (instep 1016), then a fine or exact adjustment is conducted on the focusoff-set (in step 1017).

Next, a confirmation is made on the reading, following the flow from astep 1018 to a step 1020 below. In more detail, the optical pickup 200is shifted to the above area 121 b of the apparatus information locatedat the most-inner periphery, as to conduct the reading of the data ofthe management area or region as well as adjustment on the amplitude ofthe reproduced signal (in step 1018). Then, a test or trial writing ismade in this most-inner periphery position, and the optical pickup 200is shifted to the read/write area 122 at the outer periphery so as tomake the test writing in this outer peripheral position (in step 1019).Next, the reading of the data of the management area and the adjustmenton the amplitude of the reproduced signal are conducted in this outerperipheral position (in step 1020). After completing the flows mentionedabove, the optical disc is in the ready condition.

On the optical disc under the ready condition, the optical pickup 200 iscontrolled to move or shift slowly from the inner periphery to the outerperiphery thereof always along with the spiral track(s). With this, itis possible to protect the disc from giving damages on data, which maybe caused by irradiating the laser beam on the same position if theoptical pickup is fixed, and also to lower the error in accuracyfollowing abrupt shift upon receipt of a drive command.

Though, according to the conventional art, in the above steps from 1018to 1020, the trial writing is conducted in an order from the innerperiphery to the outer periphery by shifting the optical pickup to theinner periphery after conducting the adjustment on the amplitude of thesteps 1018 and 1020, therefore it necessitates much time for theshifting of the optical pickup 200. However, according to the presentembodiment, the operations are conducted with shifting the opticalpickup 200 along the direction from the inner periphery to the outerone, the time for shifting the optical pickup 220 can be shorten, and inaddition thereto, the time for positioning the pickup 200 at a desiredposition from a position necessitating a large shifting distance, sinceeach shifting distance can be made lessened or diminished.

In this manner, according to the present embodiment, each the shiftingdistance can be lessened or diminished so as to be conductedeffectively, it is possible to shorten the time necessary to reach tothe ready condition.

Further, for conducting the reproducing operation during the fineadjustment of the focus offset, the tracking servo drive must beperformed with respect to the RAM area before the fine adjustment of thefocus offset.

Next, explanation will be given on a method for compensating a powershortage in the semiconductor laser 210, in particular when it iswriting in the fine adjustment of the FE, for example the operation flowof the trial writing in the above step 1019.

Conventionally, there can be found the optical disc apparatus which doesnot come to the ready condition if it is driven under a condition ofroom temperature of 50□ C. Studying or searching of this, the main causeof this appears to be the shortage of the power in the semiconductorlaser 210 when writing in the fine adjustment of the FE. For example, itis considered that an I-L (a relationship between electric current andpower of the semiconductor laser 210) is decreased down by 30% in thetroubled apparatus. As a measurement for this, though it can be treatedor resolved by increasing the power mentioned above, however, since thepower is very important factor for conducting the recording andreproduction of data on the optical disc, there is an anxiety orpossibility that the increased power may undesirably cause the damagesof data under the condition of around 0□ C., reversibly if the power isrisen up.

This will be explained by referring to FIG. 10 showing the result ofmeasurement. In this FIG. 10, the horizontal axis indicates acircumference temperature of the apparatus, and the vertical axis thesignal amplitude (DAC value). For example, in a case where current isconstant, a nominal amplitude of the above-mentioned semiconductor laser210 falls down in reverse proportion with increase of the circumferencetemperature. With applying the I-L compensation on this, there can beobtained a signal amplitude being constant at a target value thereof.For example, under the room temperature is around 50□ C, the targetsignal amplitude can be achieved by the compensation of 1.10.

Then, in the present embodiment, a pre-writing (trial writing) isconducted, proceeding by 1 track (about four (4) tracks) from a FE fineadjustment pattern. The value of this is taken by the front lightreceiving element (front monitor) 261 shown in FIG. 1, and thenadjustment is made on the electric current and the voltage dependingupon a front monitor value which is obtained from the front lightreceiving element 261, so that it comes to be equal to the initial setvalue, i.e., the power adjusting value within a range □10% thereof, andthen the adjusted FE fine adjustment pattern is recorded or stored. Inthe present embodiment, the above-mentioned adjustment is executedbefore the step 1019 for conducting the rest write on the innerperiphery, shown in the above FIG. 9.

As is mentioned previously, the above-mentioned front light receivingelement 261 feeds back a predetermined signal to the above-mentionedlaser driver 500, so that the signal obtained through the said frontlight receiving element 261, being compared with a preset reproductiontarget voltage, comes to be equal to the voltage. With this feedbackloop, the emission light of the semiconductor laser is controlled at aconstant in the intensity when reproducing the information, and for thispurpose there is used a voltage detecting means in the pre-write in thestage before the recording, in this embodiment. Here, the current presetvalue lies in a range from 50% up to 130% of the above power adjustmentvalue, and such a protection is applied to that the current value is setat 50% or 130% if it exceeds the rang 50% up to 130%.

The flow of this operation will be explained by referring to FIG. 11. Inthe optical disc apparatus of the present embodiment, after reading theinitial set values (in step 1101) and the data for a fine learningcontrol of the FE of groove portion (in step 1102), the pre-writing(trial writing) is conducted at a position proceeding by 1 TR (about 4sectors) from the track position of above-mentioned learning control (instep 1103). Then, the data written in the pre-write is read out bycalling up a sub-routine for a standard power for the test writing (instep 1104), and calculates the DAC power of the front monitor valuewhich is obtained from the above-mentioned front light receiving element261 (in step 1105). In this instance, when an error occurs in reading inthe above step 1104, a retry is made on other track. Then, a decision ismade whether the current preset value of the calculation resultmentioned above is within the range from 50% to 130% of the poweradjustment value (when shipping) or not (in step 1106). If decidedwithin the range, the power setting of the DAC is risen up by 10%thereof (in step 1107), while if decided to be outside of the range, acritical value is set (in step 1112). After the step 1107, the poweradjustment value increased by 10% is applied to a track record groovepotion for the FE minute learning control (in step 1108) and the routineof reproduction portion of the FE minute learning control (in step1109).

Then, it is decided whether there are sectors being equal or less thanfive (5) in the number or not, in which the value obtained by theroutine of the above reproduction portion is less than ⅓ amplitude (onethird in the amplitude) (in step 1110). In a case where the decisionresults in ES the routine for a FE minute adjustment on the groove sideis executed (in step 1111). While, when the decision results in O thetrack is changed to another one (in step 1113), and the DAC powersetting is further risen up by 10% thereof (in step 1114) so as toexecute the above step 1108.

Further, when the ⅓ amplitude occurs in the sectors greater than five(5), the re-try is made on other track.

Thus, according to the present embodiment, for practicing the pre-write,exclusive areas for conducting it are prepared or provided, beingseparated from the trial writing areas and smaller in the numberthereof. With this, it is possible to use the write area with highefficiency though having a limit (for example, 100,000 times) in thewriting operation thereon. Moreover, since the pre-write is a kind ofthe writing operation of short time period, the above effect is furtherimproved by executing the pre-write at random while changing the placesalways within the exclusive area. In addition thereto, the exclusiveareas for the pre-write are provided in the inner side of the trialwriting area by taking into the consideration the fact that the opticalpickup is rather easily shifted or operated from the inner peripherytoward to the outer periphery.

Further, according to the present embodiment, for example, theabove-mentioned exclusive areas are provided in the write area 121inside the above RAM portion 120. In more detail, the area 121 b for theapparatus information, totally having about 112 lines of tracks therein,is separately provided, i.e., 28 lines for the pre-write area (FE minuteadjustment), 70 lines for the rest-write area and 14 lines forpreservation, from inner side to outer side.

In this manner, in the flows using the pre-writing according to thepresent embodiment, first a short focus signal (i.e., the pre-writing)is executed, and takes a rest one time, during which the contentswritten with the pre-writing are read out, and then a long focus signal(i.e., the trial writing) is conducted, i.e., by repeating theoperations in plural of times, the optimal focus condition is set.

The above-mentioned flow using the pre-writing should be conducted afterthe decision of the optical disc and until it comes to be in the readycondition. Alternatively, it may conducted before the re-try when thewriting is impossible.

Next, by referring to FIGS. 12 to 18, the method for controlling thefocus of the optical disc apparatus according to the present inventionwill be explained further.

FIG. 12 is a flow chart for explaining the focus control method, FIG. 13an explanatory view for concretely explaining a pitch addressacknowledgeable area, FIG. 14 a flow chart for explaining the learningcontrol of the focus control, FIG. 15 an explanatory view for explainingthe optimal off-set value for each sector, being set by the learningcontrol of FIG. 14, and FIG. 16 an explanatory view for brieflyexplaining the optimal FE off-set values which are set by averaging inthe learning control of FIG. 14.

FIG. 17 is a flow chart for explaining the leaning control of the focuscontrol according to another embodiment, and FIG. 18 an explanatory viewfor briefly explaining the optimal FE off-set values which are set by amaximum amplitude and a decreasing rate in the learning control of FIG.14.

First, the flow chart shown in FIG. 12 is conducted before performingthe learning control which will be shown in FIG. 14 below, therebysetting up a variable region of the focus potion in the learning controlin advance. This flow is initiated at the same time when the reproducingapparatus is turned ON, for example, and is executed on the basis of thevarious output signals shown in the above FIG. 7, as well as of theabove land and groove areas, respectively.

In this flow, first, the off-set value of the focus error (FE) is set upat the initial setting value (in step S11). Namely, the abovemicro-computer 400 sets the initial setting value at the D/A converter313 and 316, which are memorized in the EPROM or the like when beingshipped out. After that, the micro-computer 400 sets up a plurality ofsteps (for example, 16 steps from +8 step to −8 step) around the initialsetting value (0) for control, as shown in attached FIG. 13, and changesthe focus position by setting the respective step values as the off-setvalue for the above focus error (FE). And, then a decision is made onreproduction of the pit(s) in the pit address area at the plural focuspositions. In this instance, as an condition for the decision onreproduction of the pit(s), by using the ID signals shown in the aboveFIG. 8(A), it is decided whether the ID signals can be acknowledged incontinuous or not in the region of one round of track. Or alternatively,also the sector number detectable within one track can be a conditionfor such the decision.

Namely, in the above FIG. 12, first, as the off-set value is set thevalue from 0 down to −8 step one by one (in step S12), then it isdecided whether the address can be reproduced or not by trying toacknowledge the pits P, P . . . in the above bit address area PA at eachof those focus positions (in step S13). As the result, if the pitaddress can be reproduced (i.e., OK in the figure), the off-set value isstored (in step S14), this process is repeated until when thereproduction of the pit address comes to be impossible (i.e., NG).Thereafter, in the same manner as mentioned in the above, setting thevalue from 0 up to +8 step as the off-set value one by one (in stepS15), making the decision in reproduction (in step S16), storing theoff-set value being reproducible (in step S17), repeating this untilwhen the reproduction comes to be impossible (i.e., NG), and finally,the off-set values within a region being variable with the learning,i.e., the off-set values with which the pit address can be recognized oracknowledged is determined by the step range (in step S18) to becompleted in the process.

As a result of this, the range in which the pits P, P . . . in the pitaddress area PA can be recognized with certainty can be set up in thesteps from −8 up to +8 around the initial off-set value (0) in the focusposition control. In more details, in the above FIG. 9(A) for example,since G is at the steps −8 and +5 for the focus control in the landarea, it is apparent that the pits P, P . . . in the pit address area PAcan be acknowledged with certainty in the region between them, at thesteps from −7 up to +4. From this, for the focus control in the landarea, it is possible to control the focus position at the optimalposition with keeping the reproduction of the pit address, by conductingthe learning control within the range of the steps from −7 up to +4.Further, it is also same to the above for the focus control in thegroove, and in an example shown in the above FIG. 9(B), it is apparentthe learning control can be conducted within the range of the steps from−4 up to +7 later.

Following to the above, an explanation will be given on the learningcontrol for controlling the optimal focus position in the above land andgroove areas in which the information is recorded respectively, byreferring to FIGS. 14 to 18. However, when a non-recorded disc isinserted, recording is conducted by driving the laser driver circuit 500in test zones assigned at the most-inner periphery and the most-outerperiphery of the disc. In the present learning control, since a relativechange is used in amplitude of the reproduced signal of the recordeddata, the setting of the recording pattern may be enough for the initialvalues which are set up in advance.

First, FIG. 14 shows a process flow of the learning control for theoptimal focus position control, briefly. First, the reproduction of thedata is conducted (in step S21). However, in this instance, as shown inthe above FIG. 8(A), at a top portion of each of the sectors ispositioned a VFO portion in which a predetermined pattern (number) ofthe pits having a predetermined width, being called T for example, andafter that follows a data (DATA) portion in which the reproduciblerecorded information is recorded. And, here, the controlling of theoptimal focus position is achieved by utilizing the intensity of thereflection light in this VFO portion. Namely, in this VFO portion, thewave-form of the reproduced signal is as shown in FIG. 8(C), however,from the above envelope detection circuit 322 (see FIG. 7) foroutputting an envelope wave-form is outputted an output as shown in FIG.8(D), i.e., a signal being always constant in the height (voltage) ifthe reflection factor is constant on the recording surface of the aboverecording medium 100. Mentioning of the reasons of adopting the 4Tpattern, it is stable with respect to fluctuation of the recordingpattern in the medium of type of phase change, and it was ascertained byexperiments that by the greatest amplitude of this 4T pattern can beobtained the focus position at the optimal condition for recording andreproducing with the land-groove method.

Then, as is apparent in the above FIG. 7, the micro-computer 400 outputsthe sample hold (S/H) signal during the period of this VFO portion, andtakes in the height of the above envelope wave-from (see FIG. 8(D)) fromthe sample hold (S/H) circuit 323 as the value of amplitude of thereproduced signal detected. The sample hold (S/H) signal in this timeand the height of the envelope wave-form to be taken in therewith, i.e.,the amplitude of the reproduced signal detected (amplitude of thereproduced signal detected) are shown in the above FIGS. 8(E) and (F).

Again returning to FIG. 14, in the learning control for the optimalfocus position control, next, the off-set of the focus error signal (FE)is set up (in step S22). Namely, here is set up the extent or limit withthe acknowledgeable region of the pit address which is obtained in thestep S18 in the above FIG. 12. In more details, for example, as shown inthe above FIG. 9(B), the region being able to be set up for the groove(G) area is from −4 to +7, and this step value is set.

Thereafter, as is explained in the above, on the basis of the amplitudeof the reproduced signals detected which are taken into from a pluralityof the sectors, the off-set value (the step values) of the focus error(FE) is obtained at which the signal amplitude in each sector becomesmaximum (step S23). And, by averaging those off-set values in the focuserror (FE) obtained for each sector, there are obtained optimal off-setvalues FEoff(L) and FEoff(G) of the focus error (FE) for the land (L)area and the groove (G) area in the recording medium 100.

However, in the above, for dissolving non-uniformity (i.e., variety) inthe reflectivity by an unit of the sector in a circumference directionof the disc, i.e., the recording medium, namely as shown in FIG. 15, forexample, and when the reproduced signals detected are different inamplitude thereof one another (see FIG. 8(F)) in each sector (from Sec.1 to Sec. 17), first, the optimal FE off-set values are obtained in eachsector (in more details, by averaging the FE off-set values of a sectorbridging over a plurality of circumferences being equal in the radialdirection). Thereafter, by averaging the FE off-set signals of allsectors, there are obtained the optimal FE off-set values FEoff(L) andFEoff(G). Explaining this by simplifying in the attached FIG. 16, forexample, in a case where there are obtained the off-set values, −1, +1and +3, respectively for the three sectors, Sec. 1 to Sec. 3, at whichthe reproduced signals detected becomes maximal, the optimal FE off-setvalue is +1 (by unit of step) by averaging them.

For obtaining the focus off-set value of this maximum value inamplitude, there are various ways, including, a finite differencemethod, calculation of the maximal position with use of approximation bya curve of second degree, and a method of obtaining from a half ofvalues at the off-set positions at right and left by decreasing by −1 dBin amplitude values from the amplitudes obtained to be almost maximal,etc. Here is explained, however, a method for obtaining at the valuebeing decreased by a predetermined value from the amplitude from whichthe almost maximum value is obtained, by referring to FIGS. 17 and 18.

In FIG. 17, as similar to the flow shown in FIG. 14, the reproduction ofdata is conducted (in step S31), and then is conducted the setting ofthe off-set of the focus error (FE) (in step S32).

Thereafter, the almost maximum value of amplitude is obtained on basisof the amplitude of the reproduced signals detected, which are takeninto from the plurality of sectors, and then the off-set positions atboth sides thereof is obtained, at which the amplitude value isdecreased down by a predetermined amount thereof from the almost maximumvalue (in steps S33, S34).

This will be explained in more detail by referring to FIG. 18. First, ina step S33, by deciding steps in a minus direction (1) from the initialset value (0) and then in a plus direction (2), one by one, the step(s)at which the value in the amplitude is lower than a predetermined valueis decided. For example, in FIG. 18, the decision starts from the step−1 and finds the decrease in the amplitude value at the step −3, thenthe decision in the minus direction (1) is or ended here. Then, itstarts from the step +1 and finds the decrease in the amplitude value atthe step +7, then the decision in the plus direction (2) is or endedhere.

Next, a half value between the both steps in the minus direction and theplus direction (in step S35). For instance, a half value +1 is obtainedbetween the step −3 and +7. Thus, this value can be the optimal off-setvalue. This value is practiced to the land (L) area and the groove (G)area, respectively.

According to this embodiment, comparing to the embodiment explained inFIG. 14, the number of steps for detecting with driving the optical discrotationally can be lowered greatly. Also, though conventionallydetection errors may occurs due to the asymmetric wave-form in theembodiment shown in FIG. 14, however with the present embodiment, suchthe error in the detection can be released. Further, with thisembodiment, not on all the initial values, the decision is completed orended at the time point when detecting the decrease in the amplitudevalue from the predetermined value in the sequential decisions in one ofthe directions of the steps, thus obtaining the shortened time fordecision. In the present instance, the decision is conducted in thedirection from 0 to −8, and then in the direction from 0 to +8, forexample, therefore the time for the decision can be shortened comparingto the method of deciding in the plus and the minus directions one byone. The present embodiment can be practiced even if the minus directionand the plus direction are replaced with each other. Moreover, thisdecision method can be applied to the decision shown in FIG. 13.

However, as is apparent from the above explanation, if the optimal FEoff-set value obtained with the above control goes beyond the range ofthe steps (i.e., from −7 to +4) set in the above step 22, the valuebeing the nearest thereto among the set values, i.e., −7 or +4 isselected as the optimal EF off-set value. Namely, with this, it ispossible to control the focus position of the above optical pickup atthe optimal position while always reading the address signal in the pitaddress area correctly. Namely, without loosing the total operation asthe reproducing apparatus due to the omission or defect of the addressinformation, the superior focus control can be obtained always.

In the explanation in the above, however, so-called the learning controlis explained, as the one method for the optimal positioning control inthe focus, however, the present invention should not be restricted tosuch the learning control only. Namely, it is apparent that the presentinvention can be also applied to even when adopting other controlmethods for performing the optimal positioning control of the focus, inthe same manner as mentioned in the above.

Further, in the explanation of the above embodiment, the explanation wasgiven only on the reproducing apparatus and the operations thereof,which reads out the information being recorded in the above opticalinformation recording medium 100 in advance. However, the presentinvention should not be restricted to the reproducing apparatus for useonly in reproducing (i.e., read-only), but further it can be applied tothe recording/reproducing apparatus of the optical information recordingmedium having a function of writing information in addition thereto.And, when applying the present invention to the recording/reproducingapparatus for the optical information recording medium, it is possibleto apply the present invention to the focus control not only whenreproducing the information but also when recording the information, inthe same manner as mentioned in the above. And also in such a case,since the address information on the recording surface of the opticalinformation recording medium can be obtained with certainty whenrecording, it would be apparent from the above explanation to obtain themore optimal recording operation of information.

1. An optical disc apparatus for recording and reproducing informationwith respect to an optical disc, comprising: means for reading controlinformation recorded in a pre-recorded area of said optical disc; meansfor conducting focus control based on a focus error signal recorded in afirst predetermined area of said optical disc; determining means fordetermining an optimum offset value of the focus error signal recordedin said first predetermined area of said optical disc; means forconducting adjustment in amplitude of a reproduced signal read from asecond predetermined area of said optical disc; and means for conductingtest-writing in a third predetermined area of said optical disc, so asto make said optical disc in a reproducible and recordable condition. 2.An optical disc apparatus as defined in the claim 1, wherein saidtest-writing conducting means conducts the test-writing at randomchanged places in said third predetermined area.
 3. An optical discapparatus as defined in the claim 1, wherein said third predeterminedarea is provided within said first predetermined area of said opticaldisc.
 4. An optical disc apparatus as defined in the claim 3, whereinsaid third predetermined area is provided in an inner side of saidoptical disc.
 5. An optical disc apparatus as defined in the claim 1,wherein said third predetermined area is provided in an outer side ofsaid optical disc.
 6. A method for making an optical disc in areproducible and recordable condition with use of an apparatus forrecording and reproducing of the optical disc having a pre-recordedarea, a first predetermined area, a second predetermined area and athird predetermined area on a surface thereof, comprising the steps of:reading control information recorded in said prerecorded area of saidoptical disc; conducting focus control based on a focus error signalrecorded in said first predetermined area of said optical disc;determining an optimum offset value of the focus error signal recordedin said first predetermined area of said optical disc; conductingadjustment in amplitude of a reproduced signal read from said secondpredetermined area of said optical disc; and conducting test-writing insaid third predetermined area of said optical disc, so as to make saidoptical disc in a reproducible and recordable condition.
 7. A method asdefined in the claim 6, wherein said test-writing is conducted bychanging places at random in said third predetermined area.
 8. A methodas defined in the claim 6, wherein said third predetermined area isprovided within said first predetermined area of said optical disc.
 9. Amethod as defined in the claim 8, wherein said third predetermined areais provided in an inner side of said disc.
 10. A method as defined inthe claim 6, wherein said third predetermined area is provided in anouter side of said optical disc.